Fluid fuel burner control system



Jan. 12, 1937. P. o. HENDERSON 2,067,699

FLUID FUEL BURNER CONTROL SYSTEM Filed Aug. 11, 1936 2 Sheets-Sheet lFIgl.

42 E41 5 222? I ,IHLM.

Jan. 12, 1937. P. o; HENDERSON 2,057,699

- FLUID FUEL BURNER CONTROL SYSTEM Filed Aug. 11, 1936 2 Sheets-Sheet 2Patented Jan. 12, 1937 NKTED STATES PATENT OFFICE This application is acontinuation in part of my application Serial No. 71,505 filed March 28,1936.

My invention relates to control circuits for fluid fuel burners of thetype which in normal operation are periodically put into and out ofoperation by a thermostat or otherwise and in which the fuel iselectrically ignited.

A primary object is to correlate the fuel feedl ing means and theigniting means sothat fuel will not be fed until the igniting means isin good operative condition to cause ignition.

Stated in another way, an important object of the invention is toprovide means for positively preventing .the delivery of fuel from theburner whenever, for any reason, maladjustment of the igniting meanswould result in failure to ignite the fuel at the burner. The inventionthus prevents waste of fuel and the occurrence of explosions consequentupon the igniting of an accumulation of unburned fuel in a firebox orthe like. A particular object of a preferred embodiment of the inventionis to make the operation of the fuel delivery means dependent on theproper electrical spacing of electrodes forming an ignition spark gap,so that fuel will not be delivered to the burner unless the electrodesare spaced properly, i. e., far enough apart to provide a sparksuificiently hot to ignite the fuel and close enough together to providea spark which will not be blown out by the blast of fuel or for anyother reason fail to ignite the fuel.

At the present time the conventional fluid fuel.

40 place after a predetermined period, generally ninety seconds, of fueldelivery. In the use of such systems serious explosions sometimes occurwhen a previously heated firebox becomes loaded with unburned fuel orwhen an igniter which 45 initially fails to function becomes operativeafter a brief period of unburned fuel delivery. By my present inventionI positively withhold the delivery of fuel to the burner and fireboxuntil the igniter is in condition to cause certain and 50 instantignition. v a I I have illustrated the invention as embodied in an oilburner of the type in which a mixture of atomized oil and air issupplied 'to a burner by a blower or equivalent pump and ignited at theburner by an electric spark which jumps between spaced electrodes. Theinvention is predicated upon the factthat for any given type of fuel andsupply line voltage a certain predetermined gap value of a particularignition apparatus is essential to a certainty of ignition. 5

By gap value I mean the distance between the effective ends of theelectrodes, i. e., the air gap through which the spark jumps. This gapvalue is exclusive of deposits on the points of the electrodes throughwhich deposits the current 1 may pass without arcing, and is thereforeseen to be not necessarily the same as the mechanical spacing of thepoints. Of course, in the case of clean points separated by air only,the gap value is identical with the distance between points. In the caseof fouled points the gap value is diminished by the thickness of foulingthrough which the current travels from electrode material to air andfrom air to electrodemateriaL The fact that with a given line voltage,ignition transformer, type of fuel, and perhaps other variables of anyparticular installation and use, a

certain predetermined spacing of the ignition electrodes is essential tocertainty of ignition may be demonstrated as follows:

Suppose that in the case of a given oil burner installation,operationwith a particular grade of fuel and on a 110 volt supply lineis found to give unfailingly certain ignition when the spark gap is'ope-quarter inch. Of course if the gap be reduced to zero, the pointsbecome shorted, no spark is produced, and ignition cannot take place.However, if the gap be reduced to a value appreciably less thanone-quarter inch, say one-eighth inch, ignition either fails completelyor becomes uncertain because such a short gap does not produce theflaming'arc essential to instant and certain ignition of the presupposedtype of oil and, in the case of constant ignition systems,

because such a short gap is readily bridged and shorted by carbondeposits, dust, droppings of boiler scale and other foreign bodies sothat a proper arc may not be maintained at all times during fueldelivery. If the gap be increased to a value appreciably greater thanthe predetermined one-quarter inch, say three-eighths inch, any of thefollowing contingencies may arise: (l) The arc is apt to become thin andcrackling, instead of fat and flaming, and hence incapable of 0 promptlyand unfailingly igniting the fuel. (2)

A comparatively small drop in the line voltage,

particularly common in rural districts, may cause complete failure ofthe arc. (3) The long thin arc is not stable and is easily blown out bythe 55 jects and purposes by means comprising simple,

inexpensive and durable instrumentalities which will be automatic andfool-proof in operation and which may be readily adjusted to accommodatesuch variables of any particular installation as he main line voltage,the type of fuel used, etc.

In the accompanying drawing Figures 1, 2, and

"3am diagrammatic illustrations of certain circuits comprising preferredembodiments of the invention.

In the accompanying diagrammatic drawing the invention is shown embodiedin certain preferred forms which have been found operative in practice.These embodiments have been selected merely to exemplify the invention,and the following description of the particular exemplifications is notto be regarded as in any way limiting the spirit and principles of theinvention to the selected embodimenta' On the contrary, the principlesof the invention are recognized as of broad application and the appendedclaims are to be deemed limited in scope only by their express terms andthe state of the prior art. Similar reference characters designateidentical or equivalent parts in each of the three figures.

Referring now to Fig. l of the drawings, reference numerals I and 2designate the main current supply lines for a burner installationoperating on fluid fuel, for example oil, which is atomized by anysuitable means and fed with a mixture of air to a burner (not shown) bya blower or equivalent pumping means (not shown) driven by an electricmotor 3. Main line 2 may be considered the'hot wire, and main line I thecold or ground wire. Positioned adjacent the burner is a pair of spacedelectrodes forming a spark gap 4. As shown, the circuit is arranged forconstant ignition, i. e., an arc is formed at gap 4 constantly duringoperation of the motor 3 to deliver a combustible. mixture from .theburner.

The ignition gap is supplied by the secondary winding 5 of an ignitiontransformer 8. This transformer may be of the type adapted to haveimpressed on its primary winding I an electro motive force of 110 volts,and'with such input to deliver a high tension difference in potential of10,000 volts to the gap when the electrodes forming the same are spaceda predetermined distance apart, say one-quarterinch.

The primary winding I of ignition transformer 6 is supplied with mainline current through the wire 8 connected to the cold wire I, thecircuit being completed through wire ,9, a balancing coil III, the coilof a relativelyrweighted relay H, the coil of a relatively sensitiverelay I2, the lead wire I3 thereof,'and a connection I4 to the hot wire2. In the connection I4 may be interposed a main switch I5 for renderingthe whole system inoperative when desired and a room thermostat or thelike It for rendering burner operation responsive to temperaturerequirements.

A motor-controlling relay H has its coil I8 connected to the cold wire Iby conductor Is, and the other terminal 20 of the coil is connected toone of a pair of contacts 2i which are normally electrically connectedby the comparatively weighted core 22 of relay ii. Current passing fromone stationary contact 2I through the movable bridge 22 to the otherstationary contact M is led by a wire 23 to movable contact 2d carriedby the core of the relatively sensitive relay I2. The contact 24cooperates with a stationary contact 25, these contacts being normallyspaced by the weight of the core, by a biasing spring or otherwise, butbecoming closed when core I2 is suitably energized. A wire 26 connectsstationary contact 25 withlead i4 and thus completes the circuit to thehot wire 2.

The circuit to the motor 3 is made through a connection 211 from thecold wire I to a contact 23 movable with the core of motor-controllingrelay Ill. A stationary contact 29 cooperates with contact 28, thesecontacts becoming engaged when the core moves against gravity or aspring bias consequent upon energization of the coil I8. From contact 23the current passes through wire 30 to the motor 3 and thence throughlead 3| and wire 32 to another contact 33 carried by the core of relayll and insulated from the other contact28 carried by the core.Cooperating with movable contact 33 is a fixed contact 34 against whichfixed contact the movable contact 33 closes at the same time thatcontacts 28 and 29 close. From contact 34 the circuit continues throughwire 35 to movable contact 24, heretofore identifled, and thence, ifcontacts 24 and 25. be closed, through them and through wires 26 and I4to the hot wire 2.

The reference numeral 36 designates a stepdown holding transformerhaving a primary winding connected by wire 31 to the cold wire I and bywire 38 to the connection I4 leading to the hot wire 2. The low voltagesecondary wind-' relay I2. The other terminal I3 of this coil hasalready been shown to be connected to wire I4, and this wire is tappedby a wire 44 to the other terminal of the secondary winding 39. whencontacts 4| and 42 are closed a circuit is completed for delivering thelow voltage output of transformer 36 to coil I2.

A branch wire 45 connects that terminal of the primary'winding I ofignition transformer 6 which is not connected to cold wire I to wire 32which is itself connected to movable contact 33 of relay I'I.

Cooperating with the core of relay I1 is a dashpot or equivalent means46 for retarding slightly the movement of the core to close contacts 33,34 and 2 8, 29 for a purpose hereinafter explained.

The numeral I0 designates any suitable loading device, such asaninductively wound coil whose value may be adjusted in any convenientmanner, as by varying the depth of insertion of. a core 41, the positionof the core being fixed as by a set screw 48.

The operation of the system is as follows:

Assuming that the main line voltage is I I0 and i the switch I5 isclosed and the thermostat II moves in response to temperaturerequirements to closed position, the circuit through primary winding Iof ignition transformer 6 is completed from main line wire 2 throughwire I4. wire I3 coil I2, coil II, coil I0, wire 9, winding I and wire 8connected to main line wire I. Coils II], II and I2 by their reactancereduce the voltage applied by this circuit to primary winding 1 to apoint considerably below 110, the exact value of which voltage may beadjusted through the medium of set screw 48 controlling the insertion ofcore 41 in coil I0. Ignition transformer secondary windpropriate toignite the fuel mixture when the gap is supplied with the full rateddelivery of the transformer 6. Let it be assumed that this predeterminedsetting of the electrodes is one-fourth inch and that the full rateddelivery of transformer B is 10,000 volts. If the electrodes be set toprovide a one-fourth inch gap the feeler spark is produced, and thecurrent which passes through the described circuit including the primarywinding I and the coils I0, II and I2 is sufficient to move the core ofthe relatively sensitive relay I2 to close contacts 24, and 4|, 42, butis not suflicient to move the relatively weighted core 22 of relay I Ito break the connection between contacts 2|. The closing of contacts 24and 25 thus energizes coil I8 of motor-controlling relay II bycompleting a circuit from hot wire 2 through wire I4, wire 26, contacts25 and 24, wire 23, contacts 2|, wire 20, coil I8 and wire I9 connectedto cold wire I. This energization of relay II moves the core thereof,relatively slowly because of the action of dashpot 46, to close contacts33, 34 and 28, 29. The closing of contacts 28, 29 and 33, 34 completesthe circuit to the motor through wire 21 connected to cold wire I,contacts 28, 29, wire 30, the motor 3, wires 3| and 32, contacts 33 and34, wire 35, contacts 24 and 25, wire 26, and wire I4 connected to hotwire 2. The motor thus becomes supplied with current from the main linesand begins to operate to drive the blower and feed fuel to the burner.Simultaneously with the beginning of motor operation, the closing ofcontacts 33, 34, essential to completing the motor circuit as justexplained, shunts out of the circuit through primary winding I ofignition transformer B the voltage reducing coils I0, I I, and I2, 55 sothat the voltage through primary winding I becomes substantially 110,delivering the full 3 rated high tension voltage to the gap 4, 10,000 inthe illustration supposed, producing at the gap 4 a hot flaming arccapable of igniting the mixture. The circuit through primary winding I,after contacts 33, 34 close to shunt out coils III, II and I2, includeswire 8 connected to cold wire I, the primary winding 1, wire 45, 'wire32, contacts 33 and 34, wire 35, contacts 24 and 25, wire 26 and wire I4connected to the hot wire 2. To hold contacts 24 and 25 in engagementafter coil I2 is shunted out of the circuit of primary winding I, asjust described, -a lowvoltage current, is supplied to coil I2 fromv thesecondary winding 39 of holding transformer 36 through lead 40, contacts4| and 42, wire 43 connected to one end of coil I2 and wire I3 connectedto the other end of the coil, which is in turn connected to wire I4 asis also the other lead 44 of secondary winding 39.

It will thus be seen that if the electrodes formcertain to ignite thefuel.

ing gap 4 are spaced sufiiciently to provide a suitable spark whensupplied with the full rated output of ignition transformer 6, the motorwill be energized and the spark produced to ignite the fuel.

Let it be supposed however that because of deterioration, loosening, orfor any other reason the gap4 has increased somewhat beyond the desiredone-fourth inch, so that the spark therein formed when the gap issupplied with the full rated output of, the ignition transformer wouldnot be The resistance of the widened gap is thus increased to a pointwhere the current which flows through the circuit ineluding primarywinding I and coils I0, II and I2 is insuficient to move the core ofcoil I2 to close contacts 24 and 25 to energize the motor- Consequentlythe firebox cannot fill with a comcontrolled relay II. The motortherefore remains inoperative and no fuel is fed to the burner.

bustible mixture which could not be ignited or might not be ignitedinstantly on issuing from the burner.

Let it be supposed, again, that the electrodes forming gap 4 have becomebridged and hence shorted by an accumulation of carbon or other foreignbody, or that they have become loosened and have moved into contact witheach other, or that they have become so closely spaced that no arcwhichcould be formed across them by the full rated output of theignition transformer would be certain to produce instant ignition. Insuch case the resistance of the diminished gap is decreased to a pointwhere the flow of current through the circuit which includes primarywinding 1 and the coils I0, II and I2 becomes increased to a value whichis sufficient to lift the weighted or comparatively heavy core 22 ofrelay II. This breaking of contacts 2| opens the circuit to themotor-controlling relay I1 and prevents the fiow of current to the motorso that the motor remains inoperative and no fuel is supplied to theburner.

It sometimes happens that the ignition transformer becomes "drowned, i.e., shorted as the result'of immersion in water. Such a transformer isincapable of supplying its full rated output to the gap and the arcingthereby produced in the gap might be insuincient to cause instant andcertain ignition. If the transformer 6 included in the present inventionshould thus become shorted the increased current supplied through it tocoil I I would open contacts 2| and prevent the supply of current to themotor in the same manner as the motor is prevented from operating whenthe electrodes forming gap 4 approach too closely to-, gether or becomeshorted, as has been explained. It will be observed that when mainswitch I5 and thermostat I6 become closed current flows through theprimary winding I of ignition transformer 6. This current continues toflow whether A or not the spacing of the electrodes forming gap 4 isappropriate for positive and instant ignition, until such time(generally 90 seconds more or less) as the usual safety controls operateto open the main circuit. These customary controls generally include athermal time delay switch or the like (not shown) which opens the maincircuit upon failure of combustion for a predetermined period. It issuch controls which the conventional burner control systems of the priorart rely upon to terminate motor operation and delivery of fuel if aftera period of some 90 seconds of such operation and delivery ignition hasnot yet taken place. It will be noted that I rely on 7 points 2| bridgedby armature 22, and conductor such instrumentalities only for openingthe circuit to the ignition transformer in case ignition does not takeplace. minate the delivery of fuel after such delivery has continued fora period of time without being ignited. As explained hereinabove, thedelivery of unignited fuel from the burner into the firebox ispositively prevented by my invention, so that there is no possibility ofthe firebox filling up with a combustible mixture which may subsequentlybecome ignited by belated sparking at the gap or improvement in thesparking or by heat stored in the firebox or stack by previous burneroperation.

The dashpot or its equivalent 46 is included as a precaution to preventthe closing of contacts 33, 84 and 28, 29 on the initial surge of arelatively heavy current through coils II and I2 (which. will of coursealmost instantly move the relatively 4 gm core of coii I2 to closecontacts 24, 25) until the heavy current passing through coil II hassucceeded in moving the relatively heavy core 22 to open contacts 2|. Inother words, if the gap be shorted or too short, the relatively lightcore of coil I2 promptly closes its contacts against their cooperatingfixed contacts and this closing is followed somewhat later by themovement of the relatively heavy core 22 to open contacts 2 I. In suchcase the dashpot or its equivalent 46 prevents the closing of thecircuit through the motor 3 during the brief space of time in whichcontacts 2| remain bridged and contact 24 is engaged with contact 25. 1

Figs. 2 and 3 illustrate simplified embodiments, and therefore in a.sense improvements, of the Fig.

1 device. In Fig. 2 for example the holding tra'nsformer and the dashpotor equivalent 46 are eliminated, and the balancing coil III, which isnot shown in Figs-2 and 3, may be added if desired; or it may be omittedon the assumption that the several coils are fixed at appropriatevalues.

The analogy of the operation of the Fig. 2

device to that of Fig. 1 is thought to be evident.

in view of the foregoing description. Briefly, when the main switch andthermostat are closed. current passes from hot wire 2 through coils IIand I2, primary 1 of the ignition transformer 6, andlead '8-"to coldwire I, producing a feeler spark at gap 4. If the relatively low voltagehigh tension current. induced in secondary 5 is within predetermineddesired limits, points 24 and 42,

which are in' Figs. 2 and 3 electrically connected, close against points25 and 4| respectively, closing the circuit (which is in parallel to thecircuit just described) to motor-controlling relay I I through lead 5|!connected to the cold wire I, points 25, 24, 42, 4|, lead 5|, coil I8,lead 52,

I4 to hot wire 2. This energization of relay I1 closespoints 53, 5'4,and on points 58, 51 and 58 respectively. The: circuit to the motor iscompleted from hot wire'2 through lead I4, points 2|, conductor 52,points 51 and 54, motor leads 59 andlifl, and lead 8 connected to-mainwire I. Si-

multaneously relays II and I2 are shunted out of primary circuit 1,which becomes completed from' hot wire-2 through lead I4, points 2|,conductor 52, points'58 and 55,lead-6I connected to the primary], andlead 8 connecting the primary to cold wire I, and to maintainmotor-controlling relay I'I energized and keep the motor in operationthe coil I8 becomes directly connected'to the main wires in parallelwith the ignition transformer supply circuit through lead I4 connectedto hot 'Wire 2, points 2|, conductor 52. connected to coil I8, conductor62, points 55 and 53. and lead 63 I do not rely on them to terconnectedto cold wire I. The connections of the transformer supply circuit andthe motorcontrolling relay I'I being in parallel assures the transformerreceiving thefull line voltage and increases the intensity of the sparkat gap 4 to the maximum possible on the line voltage. I consider thischaracteristic, common to all the illustrated embodiments, a novel andimportant feature of the invention.

Operation of the Fig. 2 modification under abnormal conditions of gapvalue is as has been described for Fig. 1. Too great a spacing of theelectrodes results in relay I2 failing to operate, and too small aspacing causes relay II to operate, opening points 2|.

In Fig. 3 the circuit is modified to include a thermal time delayswitch, designated generally 65, to delay operation of themotor-controlling relay I'I, thus serving much the same purpose as thedashpot or the like 48 of Fig. 1. In Fig. 3,

points 4| and 42 close to energize the thermal element 65, which in apredetermined short period of time warps the heat-responsive element tobridge points 68, thereby connecting coil I8 of motor-controlling relayI! with main lines I and 2, in parallel with the ignition circuit, andshunting out relays I I and I2. The connections include lead 59 frommain wire I, points 68, conductor 10 connected to coil I8, conductor IIconnecting the coil with points 2|, and lead I4 connected to main wire2. When relays II and I2 are shunted out of the transformer supplycircuit 'by the closing of points 55 and 58, as has been described inconnection with Fig. 2, thermal element 65 becomes de-energized and theconnection between points 68 is soon broken. This, however, does notresult in de-energizing relay I I, the coil of which is now connecteddirectly with the main lines, in parallel with the ignition supplycircuit, by engagement of points 53 and 55. This connection is throughlead 83 connected to wire I, points 53 and 55, connection I2 to the coilI8, conductor II from the coil to points 2|, and lead I4 connected tomain wire 2.

Abnormal gap values affect the operation of the Fig. 3 device exactly ashas been described above for Fig. 2.

It is hardly necessary to explain that when, in operating the systemhereinabove described, it is observed that combustion does not beginpromptly after the room thermostat closes or after other customaryoperating controls are actuated, it is to be concluded that the ignitiongap is defective and requires attention. The main switch should then beopened and the electrodes examined and cleaned, adjusted or replaced, sothat operation may be begun when the switch is again closed.

The specific form of the various instrumentalities shown constitutes nopart of the invention broadly considered. These instrumentalities maytake any form capable of discharging the functions required of them. Itmay be desirable, to adapt a particular embodiment of the system to usewith a wide range of different installations,

to make the action of core 22 of relay II adjustsupplying a relativelylow voltage high tension current to said gap including a relay, a motordriving said fuel delivery means controlled by said relay, and meanscontrolled by said circuit and operablev only when said low voltage hightension current lies within predetermined limits to operate said relayto start said motor and supply a higher voltage high tension current tosaid gap.

3. A fluid fuel burner control device including main line wires,meansfor delivering fuel, electrodes forming a spark gap for ignitingsaid fuel,

a circuit connected to the main line wires for initially supplyingtherefrom a relatively low voltage high tension current to said gap, andmeans controlled by said circuit and operable only when said low voltagehigh tension current lies within predetermined limits to energize saidfuel delivery means from the main line wires in parallel with saidcircuit and to supply a higher voltage high tension current to said gap.

4. A fluid fuel burner control device including main line wires, a fueldelivery means, electrodes forming a spark gap for igniting said fuel, acircuit connected to the main line wires for initially supplyingtherefrom a relatively low voltage high tension current tosaid gap, saidcircuit including a relay, a motor driving said fuel delivery meanscontrolled by said relay, and means controlled by said circuit andoperable only when said low voltage high tension current lies withinpredetermined limits to operate said relay to connect the motor to themain line wires in parallel with said circuit and supply a highervoltage high tension current to said gap.

5. A fluid fuel burner control device including main line wires, a fueldelivery means, electrodes forming a spark gap for ignitingsaid fuel,'acircuit connected to the main line wires for initiallysupplyingi'therefrom a relatively low voltage high tension current tosaid gap, said circuit including a relay, amotor driving said fueldelivery means controlled by said relay, and means controlled by saidcircuit and operable only when said low voltage high tension currentlies within predetermined limits to operate said relay to connect themotor to the main line wires in parallel with said circuit and shuntsaid relay out of said circuit, whereby the gap is thereupon suppliedwith a higher voltage high tension current. I

6. A fluid fuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel, atransformer having a secondary circuit including said gap, a motor fordriving the fuel delivery means and a circuit for energizing said motor,relay means comprisedof reactance in the transformer circuit andresponsive to a predetermined current therein for closing the motorcircuit, and means for shunting said relay means out of the transformercircuit when said motor circuit becomes closed.

7. A fluid fuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel, atransformer spark gap for igniting said fuel, a transformer having asecondary circuit including said gap, a motor for driving the fueldelivery means and a circuit for energizing said motor, relay meanscomprised of reactance in the transformer circuit, operable only whenthe current in the secondary circuit lies within predetermined limits,for closing the motor circuit, and relay means for shunting the firstrelay means out of the transformer circuit, whereby the gap is thereuponsupplied with a higher voltage current when the motor circuit becomesclosed.

9. A fluid fuel burner control device including main line wires, meansfor delivering fuel, electrodes forming a spark gap for igniting saidfuel, a circuit connected to the main line wires for initially supplyingtherefrom a relatively low voltage high tension current to said gap,said circuit including relay means comprised of reactance and atransformer in series with a portion of said reactance for supplyingsaid gap, a motor driving said fuel delivery means, and a circuit forenergizing said motor connected to the main line wires in parallel withthe first named circuit the relay means being operable, when the hightension current in the transformer circuit supplying said gap liesbetween predetermined limits, to close the main line circuit to themotor and to shunt said portion of reactance out of the first namedcircuit, whereby the circuit supplying the gap is thereupon suppliedwith a higher voltage high tension current.

10. A fluid fuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel,a'transformer supplying said gap, a. motor for driving the fuel deliverymeans and a circuit for energizing said motor, plural reactive relaymeans in circuit with the transformer, a relay controlling the motorcircuit, and a circuit including the motor-controlling relay controlledby said plural relay means, one of said plural relay means beingoperable, when a current of predetermined value traverses thetransformer circuit, to close the motorcontrolling relay circuit, andanother of said plural relay means being operable, when a current ofpredetermined greater value traverses the transformer circuit, to openthe motor-controlling relay circuit and prevent the flow of current tothe motor controlling relay, and means operable by the motor-controllingrelay for shunting said plural relay means out of the transformercircuit when said motor-controlling relay circuit becomes closed. I

11. Al fluid fuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel, atransformer having a secondary circuit including said gap and having aprimary circuit, a motor for driving the fuel delivery means and acircuit for energizing one of said plural relay means being operable,when a current of predetermined value trav erses the primary circuit, toclose the motor-controlling relay circuit, and another of said pluralrelay means being operable, when a current of predetermined greatervalue traverses the primary circuit, to open the motor-controlling relaycircuit and prevent the flow of current to the motor-controlling relay,and means operable by the motor-controlling relay for shunting saidplural relay means out of the transformer circuit when saidmotor-controlling relay circuit becomes closed.

12. A fluidfuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel, atransformer having a secondary circuit including said gap and having aprimary circuit, a motor for driving the fuel delivery means and acircuit for energizing said motor, plural relay means comprised ofreactance in the primary circuit and a relay controlling the motorcircuit, and a circuit including the motor-controlling relay controlledby said, plural relay means, one of said plural relay means beingoperable, when a current of predetermined value traverses the primarycircuit, to close the motor-controlling relay circuit and shunttheplural relay means out of the primary circuit to supply a higher hightension current to said gap, and another of said plural relay meansbeing operable, when a current of predetermined greater value traversesthe primary circuit, to open the motor-controlling relay circuit andprevent the flow of current to the motor-controlling relay.

' 13.. A fluid fuel 'burner'control device including means fordelivering fuel, electrodes forming a spark gap for igniting said fuel,an ignition transformer having a secondary circuit including said gapand having a primary circuit, a motor for driving the fuel deliverymeans and a circuit for energizing said motor, a first and second relaycomprised of reactance in the primary circuit, a holding transformerhaving a normally open low voltage secondary circuit'in parallel withsaid second relay, a relay controlling the motor I circuit, and acircuit including the motor-controlling relay controlled by said plural'relay means, said second relay being operable, when a current ofpredetermined value traverses the primary circuit, to close themotor-controlling relay circuit, shunt the first and second relays outof the primary circuit to supply a higher hightension current to saidgap, and close the secondary circuit of the the holding transformer, andsaid first relay being operable, when a current of predetermined greatervalue traverses the' primary circuit, to open the motor-controllingrelay circuit vand prevent the flow of current to the motor-controllingrelay. r

14. A fluid fuel burner control device including main line wires, meansfor delivering fuel, a

,motor driving said means, a circuit including a I transformer and a gapfor igniting said fuel, parallel connections between the main line wiresand the motor and the transformer circuit, plural reactive relays in thetransformer circuit, one

of said relays being operable, when a current of predetermined valuetraverses the transformer circuit, to close ,the motor circuit, andanother of said relay means being operable, when a current ofpredetermined greater value traverses the spaced electrodes in itssecondary circuit forming a gap for igniting said fuel and having aprimary circuit, parallel connections between the main line wires and.the motor and the primary circuit, 'plural reactive relays in saidprimary circuit, one of said relays being operable, when acurrent ofpredetermined value traverses the secondary circuit, to closethe motorcircuit, and another of said relay means being operable, when acurrentof predetermined greater value traverses the secondary circuit,to open the motor circuit and prevent theflow of current to the motor,and means operable on closing of the motor circuit for supplying thetransformer directly from said main line wires.

16. A fluid fuel burner control device including main line wires, meansfor delivering fuel, a motordriving said means, electrodes forming a malrelay and adapted to be connected thereby with the main line wires inparallel with said circuit, and means in said circuit, operable onlywhen said low voltage high tension current lies within predeterminedlimits, for energizing said thermal element to start the motor, and forsupplying a higher voltage high tension current to said gap.

17. A fluid fuel burner control device including means for deliveringfuel, "a motor driving said means, electrodes forming a spark gap, forigniting said fuel, a circuit for initially supplying a relatively lowvoltage high tension current to said gap, and means controlling themotorcircuit, including a delayed action relay controlled by said circuit andoperable only when said low voltage high tension current lies withinpredetermined limits, to energize said delayed action relay to start themotor, and for supplying a higher volt age high tension current to saidgap.

18. A fluid fuel burner control device including means for deliveringfuel, electrodes forming a spark gap for igniting said fuel, a circuithaving reactance for initially supplying a relatiyely low voltage hightension current'to said gap, and means controlled by said circuit andoperable only when said low voltage high tension current lies withinpredetermined limits to render said fuel delivery means operative, shuntat least a portion of said reactance out of said circuit and supply ahigher voltage high tension current to said PHILIP O. HENDERSON.

